My 2003 Ford Expedition EB (125,800 miles) that I have owned since mile 1, has a leak coming from or very near the transfer case.

Took it to a good local reputable shop yesterday. They hoisted the SUV. They showed me the leak and the mechanic said it appears to be coming from not the bottom, where the six black star screws mate the case together but from the top, and the old Mercon fluid is running down to the bottom of the case.

Today, I went back to him. He drained and refilled the case with two quarts of Mercon. The old Mercon was black, the color of the leaking fluid. The leak by the way, is very, very slow. Several days ago, I layed on the ground and tried to use my star socket set and could tighten about three or four of the six star screws about 1/4 of a turn. The mechanic told me to drive it for a week or so and come back. He has a place he can send the case to for a reseal, if needed. Total cost if that is all that is needed: $640. 4X4 system functions great. Shifts to 4High and 4Lo and locks hubs great.

I am great with preventative maintenance, but I am sorry to say, never had my transfer case fluid changed in 13 years until today! My excuse is that the Ford Maintenance Guide that came with my SUV says nothing about changing "Transfer Case" fluid. I went back through it today. It does of course say change the the transmission fluid, which I have had that done. But two different systems.

Questions:

Is it common for the transfer case on an Expedition to need a reseal or could it be something else leaking going in to, or, near the transfer case, which won't require the transfer case to be removed?
(like to start with the least expensive possible solutions than work up from there)

Typical cost for a transfer case reseal?

... By the way, when we were up under the vehicle Thursday, he showed me that my rear axle is leaking too! $250 to fix that leak. I will get that fixed.

Thanks for any and all advice.

 

Could it be the breather hose on top? Mine was split, but didn't leak. I noticed it while servicing the gear selector linkage. Mine is an '05 though, so not sure what the differences are.

 

I don't think it's unrealistic for a seal to start leaking after 12 years.

 

Somewhat of an update:

I already had a Saturday appointment scheduled with my local Firestone, so I kept it, and took in for them too look. They had me underneath the vehicle too. Didn't hurt to get a second set of professional eyes and another quote.

One day after cleaning the exterior of the transfer case and changing its Mercon - it is bone dry. In light of posts on this forum about a "breather tube" we could not find it (or maybe over looked it). Not even the shop manager seemed to be able to locate the breather tube - but so far in 24 hours and about 50 miles of driving - dry.

... But what is definitely NOT dry:

passenger rear outer shaft seal - dripping - time to get that replaced.

It looked like the driver side rear outer shaft seal might beginning to start to look as it looked like a drop of differential oil was beginning to "well up" on the underside of it... But definitely the pax rear side needs replacement as soon as I can get it in for service.

To be fair, the first shop, one that changed out transfer case's Mercon and cleaned the outside of the transfer case, also pointed out the passenger rear shaft axle seal leak - but at that time, the transfer case looked "uglier" with old fluid on its outside.

 

Well, mine is an '05, so yours might not have a breather tube in the same place...

 

I also have a 2003 that is approaching 84k miles and also has a small leak coming from or very near the transfer case rear cover. I'll need to get a better look at it later with better light and the truck up on stands. I can't even try tightening the black star screws you mentioned because the fastener heads are completely rusted out. They look like a circle inside as all the protruding star portion has been consumed on the lower bolts. I did change the fluid once years back. Anyway, wondering if the original poster found the back case cover just needed a reseal or if it was something else???

 

I can't believe it has already been just over five years since I started this thread.... But looked back in my maintenance log. I had the 4X4 transfer case fluid changed 12/4/2015 at 125,803 miles by Southern Wake Auto with Mercon ATF. The transmission system uses something different; Mercon V. On 12/9/2015 I had the same shop, at 125,968 miles replace both rear axle differential seals with National Seals and the 75W90 gear oil.

I haven't thought twice about anything in this thread since. Today, the Expedition is at 190,000 miles, just had and oil/filter change and alignment check two days ago. The 4X4 transfer case runs normally, although I rarely need 4X4 - did use it in early February in Beech Mountain, NC to get out of ice/snow covered back roads, and test all the 4X4 settings about once a month. Doing well. I see nothing in my records of getting the transfer case resealed, just the transfer case fluid changed back on the date in December 2015 above as mentioned.

 

It's a curse, the older we get the faster time goes by.